Study

Monitoring an endangered freshwater turtle management program: effects of nest relocation on growth and locomotive performance of the giant South American turtle (Podocnemis expansa, Podocnemididae)

  • Published source details Jaffé R., Peñaloza C. & Barreto G.R. (2008) Monitoring an endangered freshwater turtle management program: effects of nest relocation on growth and locomotive performance of the giant South American turtle (Podocnemis expansa, Podocnemididae). Chelonian Conservation and Biology, 7, 213-222.

Actions

This study is summarised as evidence for the following.

Action Category

Relocate nests/eggs to a nearby natural setting (not including hatcheries): Tortoises, terrapins, side-necked & softshell turtles

Action Link
Reptile Conservation

Head-start wild-caught reptiles for release: Tortoises, terrapins, side-necked & softshell turtles

Action Link
Reptile Conservation
  1. Relocate nests/eggs to a nearby natural setting (not including hatcheries): Tortoises, terrapins, side-necked & softshell turtles

    A replicated, controlled study in 2003 on one river in Venezuela (Jaffé et al. 2008) found that relocating Arrau turtle Podocnemis expansa nests led to no difference in hatching success, but higher mortality during a year in captivity compared to turtles from naturally incubated nests. There was no significant difference in hatching success between relocated and natural nests (54–98%), but mortality during the first year was higher for turtles from relocated nests (relocated: 13 of 108, 12%; natural: 1 of 112, <1%). At two location on the shell, relocated turtles had more physical abnormalities than naturally incubated turtles (relocated: 74% and 77%; naturally incubated: 19% and 33%), whereas at a third location the number of physical abnormalities was similar (relocated: 4%; naturally incubated: 5%). In February 2003, six nests were excavated and reburied 1.5 km further up the riverbank. In April 2003, hatchlings from the relocated nests, as well as hatchlings from four naturally incubated nests were collected and moved to captivity. A total of 230 turtles (up to 28 turtles/nest) were included in the study and kept in captivity for up to a year.

    (Summarised by: William Morgan)

  2. Head-start wild-caught reptiles for release: Tortoises, terrapins, side-necked & softshell turtles

    A replicated, controlled study in 2003 on one river in Venezuela (Jaffé et al. 2008) found that first-year mortality of Arrau turtles Podocnemis expansa during head-starting in captivity was higher for turtles from relocated nests compared to those from naturally incubated nests. First-year mortality was higher for turtles from relocated nests compared to natural nests (relocated: 13 of 108, 12%; natural: 1 of 112, <1%). Turtles from relocated nests had more physical abnormalities than naturally incubated turtles in two locations on the shell (relocated: 74%, 77%; natural: 19%, 33%), but a similar number at a third location on the shell (relocated: 4%; natural: 5%). There was no significant difference in hatching success between relocated and natural nests (54–98%). In February 2003, six nests were excavated and reburied 1.5 km further up the riverbank. In April 2003, a total of 230 hatchlings from the relocated nests and four naturally incubated nests (up to 28 turtles/nest) were collected. Turtles were head-started in a holding tank for up to one year and fed with high-protein fish meal before being released at their beach of origin.

    (Summarised by: William Morgan)

Output references
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